Fuse plug



Feb. 25, 1947. H, A, P TER ON 2,416,494

FUS'E' PLUG Filed Feb. 9 1944 IN V EN TOR.

HAROLD A P5795550 Patented Feb. 25, 1947 UNITED STATES PATENT OFFICEFUSE PLUG Harold A. Peterson, Cedar Mills, Oreg.

Application February 9, 1944, Serial N 0. 521,672

1 Claim.

This invention relates to fuse plugs and is particularly adapted to beused in connection with socket and cartridge fuses.

The present improvement consists of positively separating the fusingmetal by insulation when an overload takes place, thereby preventing anexplosion or are continuing across the fuse break or gap. This improvedmechanism for insulating the gap in the fuse also indicates thecondition of the fuse without removing the plug.

The primary object of my invention is the applying of a pressure uponthe fusing metal of a fuse plug that will cause a rapid and clean breakin the electric circuit, at the same time providing an insulating wallbetween the fused points when the fusing takes place.

Another object of my invention is to provide a fuse plug that can bereconditioned by merely replacing the fuse metal.

A further object of my invention is to reduce arcing at the fusing pointof the fuse when an overload takes place.

A still further object of my invention is that the renewable fuseelement of a predetermined calibration will only fit the plug for whichit was intended.

And another object of my invention is to provide a means of readilyindicating when the fuse has been blown.

These and. other incidental objects will be apparent in the drawings,specification and claims.

Referring to the drawings:

Figure 1 is a sectional side elevation of my new and improved fuse plug.

Figure 2 is a partial sectional view, illustrating the removable bodyportion of the fuse plug removed from its socket after the fuse has beenseparated.

Figure 3 illustrates the removable body portion of the fuse plug inperspective.

Figure 4 illustrates a fuse metal removed from the plug in perspective.

Figure 5 is an end view, partially in section, taken on line 55 ofFigure 1.

Figure 6 is a fragmentary sectional end view taken on line fi-G ofFigure 2 illustrating the condition after the fuse has been separated orblown.

Figure '7 is a modification of the above views.

Figure 8 illustrates my new and improved plug adapted to be used on acartridge type fuse, the view being partially in section for convenienceof illustration.

Figure 9 is a plan view of the assembled plug as shown in Figure 8.

Figure 10 is a partial vertical section of a modification of theinvention.

In the drawings:

The main body of the plug of the socket or screw-in type is indicated bynumeral I, having the metal screw band 2 encircling the same. The band 2has an upright contact bar 3 extendin up within the socket 4 of the bodyof the plug l. Another contact bar 5 extends upwardly within the body orsocket 4, being held in position by the contact terminal 6. Both thebars 3 and 5 are insulated apart within the body or socket 4 of the fuseplug.

A removable plug 1 is adapted to be inserted within the socket 4. Thisplug consisting of insulation, having a slot 8 across its lower end forreceiving the fuse metal strip 9. The fuse strip consists of acalibrated bridge l0 and upright legs I I which are turned in at l2 forengaging the shoulder l3 of the plug 1, holding the fuse metal in placeon the plug.

These upright legs hold the fuse strip in place within the slot 8, atthe same time provide for contact engagement with the bars 3 and 5within the main body portion of the fuse plug. Referring to Figure 1, itwill be seen that an electrical circuit has been completed through theterminal 6, bar 5, leg I l of the fuse metal, the fusing metal at H),leg I I, contact bar 3 and band 2. Referring to Figure 2, the fuse barIn is shown burned through, the fuse metal bein separated at I4. In fuseplugs heretofore, there has been an are created when the fuse metal wasburned through by an overload. In my plug the fused ends of the fusematerial are separated apart when the break takes place. A wedge [5 hasits lower end resting on the fuse metal at its lower end It, having astem I1, extending upwardly therefrom terminating in an indicatingbutton IS. The button l9 acting as an indicator of the condition of thefuse.

A spring 20 engages the main body of the plug at 2| at its upper end,having its lower end resting upon the Wedge [5 at 22. The compression ofthis spring causes a downward pressure upon the wedge IS. The purpose ofthis pressure is to separate the fuse rapidly when the fusing takesplace and instantly insulating the points of the fuse metal after thebreak takes place. This is one of the primary objects of my invention,the reducing of the arcing when the fuse is blown and the complete andpermanent breaking of the electric circuit.

Referring to Figure 6, it will be observed that the wedge [5 completelybridges the slot 8 and enters the socket ISA. This insure completeinsulation at the break. The indicator l9 indicates the condition of theplug at all times.

Referring to Figure 7, a slight modification has been made in theoperation of the plug, in that the lower part of the socket 6 is filledwith an insulating material 23. This insulating material has a socket 24for receiving the wedge after it passes through the fused metal. Thistype of plug not only insures. insulation between the fuse metal itself,but a complete partition or insulator between the contact bars 9 and 5within the main body of the fuse plug.

Referring to Figure 8, my new principle is illustrated being adapted tothe cartridge type of fuse. In this type, the insulating wedgecompletely separates the fuse metal itself within the plug '5 and theupright contacts 25 and 26 of the fuse body 2?.

Figure 10 illustrates a modified embodiment of the invention wherein theplug 1 has two fusing strips 35 and 36 respectively. The lower endportion of the strip 35 is horizontally disposed, as

shown at 35A. Hinged to the lower end of strip 36 is a bar 31 having itsfree end resting on the horizontal portion 35A. Wedge l5 bears againststrip 3'3. This strip 35 is made of an element which curls or bends whensubjected to a determinable maximum current, hence, when the current isincreased beyond a predetermined maximum, strip 36 curls or bends andconsequently disengages strip 3'! from horizontal portion 35A, thusopening the circuit to which members 35 and 36 are connected. As thestrip 31 becomes released from horizontal portion 35A, the plunger I5moves downward and separates the two bodies, forming an effectivedielectric therebetween.

I do not wish to be limited to this particular mechanical construction,as my invention may be adapted to other forms of embodiment, stillcoming within the scope of the claim to follow.

What I claim is:

A fuse plug interiorly formed to provide a socket fully open at the top,conducting strips on the interior of the plug connected to contacts onthe outer wall of the plug, a member slidable in the socket and havingan exterior conductor in electrical contact with the conductors in thesocket, the member being formed at its lower end with a transverse slotand with a vertical bore at right angles to the slot, the conductor onthe member including a fusible section arranged in and bearing againstthe upper wall of the slot when the conductor on the member is in place,a wedge element movable in the bore and having a pointed end in contactwith the fusible element of the conductor carried by the member, aspring in the bore overlying the wedge element and serving to move saidelement downwardly following fracture of the fusible element in theconductor carried by the member, the side Walls of the slot being eachformed with a recess to receive and limit the movement of the wedgeelement following fusion of the fusible strip, the slot being of a widthto accommodate the simiiar dimension of the fusible strip, the recessesin the walls of the slot serving to receive the pointed end of the wedgemember following fusion of the fusible strip to maintain the end of thewedge member in a fixed relation in the slot to insure completeseparation of the fused ends of the fusible strip, to prevent arcing ofthe ends of the fusible strip and completely diverging the ends of thefuse s ip within and between the walls of the slot.

HAROLD A. PETERSON.

REFERENCES CITED The foilowing references are of record in the file ofthis patent:

UNITED STATES PATENTS Number Name Date 2,129,309 Stewart Sept. 6, 1938590,750 Cartwright Sept. 28, 1897 1,050,062 Johnston Jan. 7, 19131,337,806 Wells Apr. 20, 1920 1,751,055 Pelletier et a1 Mar. 18, 1930710,056 Haskins Sept. 30, 1902 1,061,894 Baker May 13, 1913 1,952,279Peterson Mar. 27, 1934

